The area of this invention is a plumbing device and a device and the method of using same to carry a point in an exact vertical direction. In particular, this invention relates to a location surveying and layout device capable of carrying points from floor surface to floor surface in a multi-story building and is particularly suitable for establishing and determining the accuracy of "building axis lines" which are the reference points to control the construction of multi-story buildings.
The common construction level uses a curved tubular vial level attached to a straight edge. When the straight edge is abutted to a surface of a vertical member to test plumb, the test is accurate only in one horizontal direction. Multiple tests must be run on the sides of the vertical member to make sure the member is not tilted toward or away from the tubular vial level. There is a great need for a level that in one test determines if the vertical member is plumb.
In the construction of multi-story buildings, upper floors are commonly reinforced poured concrete. The concrete is poured on to plywood surfaces supported by trusses. In order to provide accurate locations of apertures such as pipe chases, air conditioning ducts, elevator shafts, stairwells and the like, forms are positioned on the plywood surface so that after the concrete is poured, the forms are removed leaving apertures of proper size and position in the floor for the working component of the building. There is a continuing need to accurately and quickly position these forms on the plywood base. This is done by measurements from "building axis lines" which are essentially center lines drawn on each floor surface. All of the trade persons are waiting for the surveyor to complete these building axis lines so that the forms may be accurately positioned. Time and accuracy are an extremely important commodities during the building construction process.
In particular, in the construction of buildings of more than one story, it is necessary to transfer points vertically, from one level to another level. "Building axis lines" are determined at ground level, using standard surveying techniques. These axis lines are used as starting positions for all measurements in the determination of location of various points within the construction. Any error in the building axis lines results in error alignment of the building or in the location of fixtures within the building. These errors may be multiplied many times over if the errors are carried upwardly within the building structure While it is relatively easy to determine the building axis lines at ground level, it is considerably more complicated and substantial errors result as these axis lines are taken from the ground level and transferred upwardly to the various floors of the building. For high rise buildings, the difficulties are accentuated. A present method is to use a transit outside the building, determining points at each floor all the way from ground level and reading those points inwardly to determine the building axis line on each floor.